Influence of laminar flame speed on turbulent premixed combustion

Abstract To guide ultra-compact combustor (UCC) engineering, simulations were conducted about turbulent premixed combustion in a high acceleration field which is called high-g combustion, along with a detailed investigation on the evolution of turbulent premixed flame in a rotating tube of stoichiometric propane-air. The rotation of the tube was mimicked by modified momentum source term in the unsteady 2D simulations to decouple the centrifugal force and the Coriolis force, the latter of which was usually neglected in previous reports. A good agreement was found between the simulation result and experimental data, along with a discovery of the phenomenon that flame speed was accelerated by the imposed acceleration field. Further study indicated that the flame acceleration phenomenon can be attributed to the flame corrugation induced by the Rayleigh–Taylor instability (RTI). The Coriolis force was found to be non-negligible in high-g combustion since the Coriolis acceleration could be at the same magnitude as the centrifugal acceleration, and the observed flame speed was nearly 20% lower without the Coriolis force. The current study revealed that the high-g combustion in an open chamber due to the absence of pressure wave/flame front interaction could not be fully compatible with predictions derived from closed chamber experiments and that the Coriolis force could not be ignored in the high-g combustion process.

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A Numerical Study of Weakly Turbulent Premixed Combustion with Flame Speed Closure Model

10.4271/2003-01-1839 ◽

2003 ◽

Cited By ~ 1

Author(s):

Andrei N. Lipatnikov ◽

Jerzy Chomiak

Keyword(s):

Numerical Study ◽

Flame Speed ◽

Premixed Combustion ◽

Closure Model ◽

Turbulent Premixed Combustion ◽

Turbulent Premixed

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Simulations of gasoline engine combustion and emissions using a chemical-kinetics-based turbulent premixed combustion modeling approach

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407016661448 ◽

2016 ◽

Vol 231 (6) ◽

pp. 743-765 ◽

Cited By ~ 6

Author(s):

Shiyou Yang ◽

Eric Pomraning ◽

Ming Jia

Keyword(s):

Flame Front ◽

Chemical Kinetics ◽

Adaptive Mesh Refinement ◽

Laminar Flame ◽

Operating Conditions ◽

Premixed Combustion ◽

Turbulent Premixed Combustion ◽

Combustion Modeling ◽

Modeling Approach ◽

Turbulent Premixed

This work presents a turbulent premixed combustion modeling approach which is based on chemical kinetics. In this approach, the smallest length scales are of the order of 0.1–1.0 mm for typical engine simulations with a Reynolds-averaged Navier–Stokes turbulence model and, after adaptive mesh refinement technology is used to consider the magnitude of the subgrid field, the Reynolds-averaged Navier–Stokes turbulent flow field can be well resolved. For solution of the flame front, an artificially thickened laminar flame concept is introduced to balance the computational accuracy and the computational cost. Around the artificially thickened laminar flame front, a special grid resolution strategy is designed, i.e. using much finer resolution in the normal direction of the flame front and typical adaptive mesh refinement resolution in the other two perpendicular directions. Then, chemical kinetics can be applied to the chemistry process which occurs in the flame front. To use this chemical-kinetics-based turbulent premixed combustion modeling approach better, a good chemical kinetics mechanism is very important. For this reason a practical primary-reference-fuel chemical kinetics mechanism is improved and validated in present work. The newly improved mechanism resolves several issues in the existing mechanisms, including unrealistically fast autoignition reactions and limited laminar flame speed validation. After reoptimization of those laminar-flame-speed-related reactions, the new mechanism can correctly compute the laminar flame speeds for a wide range of Ford spark ignition engines and for various operating conditions. Using this combustion modeling approach together with the new mechanism, simulations of the combustion and the emissions of several spark ignition engines for typical operating conditions were carried out. The simulated in-cylinder pressures, the simulated burn rates, and the simulated emissions including the brake specific carbon monoxide emissions, the nitrogen oxide emissions, and the unburned hydrocarbon emissions are compared with the experimental data, and very good agreement is found without tuning any model constants.

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The effect of magnetic field variations in a mixture of coconut oil and jatropha on flame stability and characteristics on the premixed combustion

EUREKA Physics and Engineering ◽

10.21303/2461-4262.2021.001996 ◽

2021 ◽

pp. 13-22

Author(s):

Dony Perdana ◽

Satworo Adiwidodo ◽

Mochamad Choifin ◽

Wigo Ardi Winarko

Keyword(s):

Magnetic Field ◽

Vegetable Oil ◽

Laminar Flame ◽

Coconut Oil ◽

Flame Speed ◽

Premixed Combustion ◽

Flame Stability ◽

Laminar Flame Speed ◽

Magnetic Field Variations ◽

Ratio Range

This study investigates the effect of attracting and repels magnetic fields with the materials of vegetable oil in the form of a mixture of coconut oil and jatropha (B50) against the behavior of stability and characteristics of flame in the process of premixed burning. The fuel for a mixture of vegetable oil of 600 ml was filled into the boiler heated with a gas stove to be evaporated at a temperature of 300 °C and 3 bar pressure was kept constant was mixed with air from the compressor in the burner room. Then a flame was ignited at the end of the nozzle to form a diffusion flame, the flame formed was then given north (N) and south (S). The results showed that the flame speed of the attractive magnetic field was 52.22 cm/sec, the repulsive magnetic field was 50.49 cm/sec while without a magnetic field was 49.79 cm/sec. The increase in the laminar flame speed in the attractive magnetic field is caused by the electron spin becoming more energetic and due to the change in the spin of the hydrogen proton from para to ortho. The attractive magnetic field has the strongest effect on increasing the flame speed. This makes the flame more stable in the equivalency ratio range of 0.75–1.17 compared to without a magnetic field in the same equivalency ratio range. This was so because O2 where it is in nature of paramagnetic was pumped more crossing the flame from south to north poles whereas the heat brought by H2O in nature of diamagnetic was pumped more crossing north to south poles. Whereas on the repel magnetic field, it was hotter when brought by H2O pumped into the flame whereas O2 tended to be pumped going out of the flame. This caused the combustion in the flame was smaller and the reaction was not maximum. As a consequence, the laminar flame speed was more lacking and the reaction was not to the fullest. As a consequence, the laminar flame speed in the repel was fewer than the attract magnetic field

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Evaluation of Turbulent Flame Speed Model for Turbulent Premixed Combustion Flow around Bluff Body

Journal of the Korean Society of Marine Engineering ◽

10.5916/jkosme.2011.35.1.082 ◽

2011 ◽

Vol 35 (1) ◽

pp. 82-88

Author(s):

Nam-Seob Park ◽

Sang-Cheol Ko

Keyword(s):

Bluff Body ◽

Turbulent Flame ◽

Flame Speed ◽

Premixed Combustion ◽

Turbulent Premixed Combustion ◽

Turbulent Flame Speed ◽

Combustion Flow ◽

Turbulent Premixed

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A comparison of entrainment velocity and displacement speed statistics in different regimes of turbulent premixed combustion

Proceedings of the Combustion Institute ◽

10.1016/j.proci.2020.06.241 ◽

2020 ◽

Author(s):

Nilanjan Chakraborty ◽

Markus Klein ◽

Hong G. Im

Keyword(s):

Premixed Combustion ◽

Turbulent Premixed Combustion ◽

Entrainment Velocity ◽

Displacement Speed ◽

Turbulent Premixed

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A data-driven subgrid scale model in Large Eddy Simulation of turbulent premixed combustion

Combustion and Flame ◽

10.1016/j.combustflame.2021.111486 ◽

2021 ◽

Vol 231 ◽

pp. 111486

Author(s):

Junsu Shin ◽

Yipeng Ge ◽

Arne Lampmann ◽

Michael Pfitzner

Keyword(s):

Large Eddy Simulation ◽

Premixed Combustion ◽

Data Driven ◽

Scale Model ◽

Subgrid Scale ◽

Turbulent Premixed Combustion ◽

Eddy Simulation ◽

Large Eddy ◽

Subgrid Scale Model ◽

Turbulent Premixed

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A Numerical Study on the Reactivity of Biogas/Reformed-Gas/Air and Methane/Reformed-Gas/Air Mixtures at Gas Turbine Relevant Conditions

Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration; Organic Rankine Cycle Power Systems ◽

10.1115/gt2016-56655 ◽

2016 ◽

Cited By ~ 3

Author(s):

Pablo Diaz Gomez Maqueo ◽

Philippe Versailles ◽

Gilles Bourque ◽

Jeffrey M. Bergthorson

Keyword(s):

Gas Turbine ◽

Laminar Flame ◽

Numerical Study ◽

Flame Temperature ◽

Flame Speed ◽

Flame Stability ◽

Laminar Flame Speed ◽

Fuel Reforming ◽

Numerical Work ◽

Chemical Effects

This study investigates the increase in methane and biogas flame reactivity enabled by the addition of syngas produced through fuel reforming. To isolate thermodynamic and chemical effects on the reactivity of the mixture, the burner simulations are performed with a constant adiabatic flame temperature of 1800 K. Compositions and temperatures are calculated with the chemical equilibrium solver of CANTERA® and the reactivity of the mixture is quantified using the adiabatic, freely-propagating premixed flame, and perfectly-stirred reactors of the CHEMKIN-Pro® software package. The results show that the produced syngas has a content of up to 30 % H2 with a temperature up to 950 K. When added to the fuel, it increases the laminar flame speed while maintaining a burning temperature of 1800 K. Even when cooled to 300 K, the laminar flame speed increases up to 30 % from the baseline of pure biogas. Hence, a system can be developed that controls and improves biogas flame stability under low reactivity conditions by varying the fraction of added syngas to the mixture. This motivates future experimental work on reforming technologies coupled with gas turbine exhausts to validate this numerical work.

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